Heated and humidified CO2pneumoperitoneum inhibits tumour cell proliferation, migration and invasion in colon cancer

Minimally Invasive Surgery: Is It a Risk Factor for Postoperative Peritoneal Metastasis in pT4 Colon Cancer?

BACKGROUND

Performing laparoscopic surgery for T4 colon cancer remains controversial because of concerns about whether its oncologic outcomes are comparable to those of open surgery, and postoperative peritoneal metastasis (PM) has been reported to occur more frequently in laparoscopic colectomy for T4 colon cancer. We investigated whether minimally invasive surgery (MIS) demonstrated a higher PM rate than open surgery and analyzed the risk factors for PM in pT4 colon cancer.

METHODS

This study included 392 patients with pT4 colon cancer who underwent curative surgery at a referral hospital between January 2000 and December 2018. Patients with previous neoadjuvant therapy, synchronous malignancy, metastasis, or those who underwent hyperthermic intraperitoneal chemotherapy were excluded.

RESULTS

The MIS group had fewer high-risk clinical features, such as tumors too large for endoscope admission or complications like perforation and fistula. The group also exhibited shorter operative time, intraoperative blood loss, multivisceral resection, hospital stay, fewer postoperative complications, smaller tumor size, lower pT4b ratio, and higher pN+ rates. Multivariate analysis revealed that high-risk clinical features, MIS, pT4b, pN+, tumor size < 5 cm, high histological grade, lymphovascular invasion, and postoperative complications were significant risk factors for PM. During the median 59-month follow-up, the 5-year cumulative incidence of PM was elevated in the MIS group (17.5% vs. 8.2%; P = 0.057). No significant differences were observed in the 5-year overall and disease-free survival rates.

CONCLUSIONS

Minimally invasive surgery increases the risk of postoperative PM in patients with pT4 colon cancer. Surgeons may require thorough tumor staging and radical resection to prevent PM.

Effects of Warmed and Humidified CO2 Surgical Site Insufflation in a Novel Experimental Model of Magnetic Compression Colonic Anastomosis

Background. Pneumoperitoneum insufflation with warmed and humidified carbon dioxide (WH-CO2) can prevent heat loss and increase tissue oxygenation. We evaluated the impact of localized WH-CO2 insufflation on the anastomotic healing process. Methods. Sixty male Wistar rats were randomized: Group 1 (control, n = 12), Group 2 (cold and dry CO2, CD-CO2, n = 24), and Group 3 (WH-CO2, n = 24). A magnetic compression side-to-side colonic anastomosis was performed under 60-minute local abdominal CO2 flow insufflation. Animal temperature was recorded. IL-1, IL-6, and CRP levels were assessed before and after insufflation and on postoperative day (POD) 7 and POD 10. Endoscopic follow-up was performed on POD 7 and POD 10. A burst pressure (BP) test of the specimen was performed on POD 10, and histopathological analysis was then performed. Metabolomics of the anastomotic site was determined. Results. Seven rats (5 CD-CO2 group, 1 WH-CO2 group, and 1 control group) died during the survival period. Necropsies revealed intestinal occlusions (n = 2). One additional rat from the CD-CO2 group was sacrificed on POD 7 due to intestinal perforation. The postoperative course was uneventful in the remaining cases. There was no difference in BP among the groups. Thermal monitoring confirmed that WH-CO2 insufflation was effective to reduce heat loss. IL-1 levels were statistically and significantly lower on POD 10 in the WH-CO2 group than the CD-CO2 group but not lower than the control group. CRP levels, histopathology, and metabolomics did not show any difference between the 3 groups. Conclusions. WH-CO2 was effective to preserve core temperature. However, it did not improve anastomotic healing.

Pneumoperitoneum in Veterinary Laparoscopy: A Review

Objective: To review the effects of carbon dioxide pneumoperitoneum during laparoscopy, evaluate alternative techniques to establishing a working space and compare this to current recommendations in veterinary surgery. Study Design: Literature review. Sample Population: 92 peer-reviewed articles. Methods: An electronic database search identified human and veterinary literature on the effects of pneumoperitoneum (carbon dioxide insufflation for laparoscopy) and alternatives with a focus on adaptation to the veterinary field. Results: Laparoscopy is the preferred surgical approach for many human and several veterinary procedures due to the lower morbidity associated with minimally invasive surgery, compared to laparotomy. The establishment of a pneumoperitoneum with a gas most commonly facilitates a working space. Carbon dioxide is the preferred gas for insufflation as it is inert, inexpensive, noncombustible, colorless, excreted by the lungs and highly soluble in water. Detrimental side effects such as acidosis, hypercapnia, reduction in cardiac output, decreased pulmonary compliance, hypothermia and post-operative pain have been associated with a pneumoperitoneum established with CO2 insufflation. As such alternatives have been suggested such as helium, nitrous oxide, warmed and humidified carbon dioxide and gasless laparoscopy. None of these alternatives have found a consistent benefit over standard carbon dioxide insufflation. Conclusions: The physiologic alterations seen with CO2 insufflation at the current recommended intra-abdominal pressures are mild and of transient duration. Clinical Significance: The current recommendations in veterinary laparoscopy for a pneumoperitoneum using carbon dioxide appear to be safe and effective.

High-pressure artificial pneumothorax promotes invasion and metastasis of oesophageal cancer cells

OBJECTIVES

This study aimed to investigate the viability, apoptosis, invasion and metastasis of oesophageal cancer cells in a simulated artificial pneumothorax model and to explore its potential mechanism of action.

METHODS

Oesophageal cancer cells were subjected to a simulated thoracoscopic CO2 pneumothorax environment with different pressures and exposure times (low-pressure group: 8 mmHg 1 h or 8 mmHg 4 h; high-pressure group: 12 mmHg 1 h). Cell viability, apoptosis, invasive capacity and mRNA expression of adhesion- and metastasis-related molecules in each group were detected. To explore in greater detail the potential reasons for the changes in biological behaviour under the high-pressure CO2 environment, we designed 3 additional experimental groups: (i) high-pressure group, (ii) hypoxia group and (iii) pH decrease group. An miRNA microarray analysis was performed by comparing 2 paired samples of cells from the high-pressure group and the control group.

RESULTS

Treatment with high-pressure CO2 pneumothorax significantly increased the cell viability (P < 0.001) and the cell invasion (P < 0.001). Significantly higher expression of adhesive- and metastasis-related molecules was also observed. Further experiments indicated that the high-pressure CO2 pneumothorax might increase cell invasion and metastasis through the high pressure and decreased pH. The miRNA microarray analysis results suggested that several potential pathways related to cancer development: the RhoA pathway, the PI3K-Akt signalling pathway and the MAPK signalling pathway.

CONCLUSIONS

The application of high-pressure CO2 pneumothorax promoted the invasion and metastasis of oesophageal cancer cells through high pressure and decreased pH. This process might be related to several signalling pathways.

Effect of pneumoperitoneum with warmed humidified or standard-temperature carbon dioxide during laparoscopy on core body temperature, cardiorespiratory and thromboelastography variables, systemic inflammation, peritoneal response, and signs of postoperative pain in healthy mature dogs

OBJECTIVE To evaluate effects of pneumoperitoneum created with warmed humidified CO₂ (WHCO₂) during laparoscopy on core body temperature, cardiorespiratory and thromboelastography variables, systemic inflammation, peritoneal response, and signs of postoperative pain in healthy mature dogs. ANIMALS 6 mature purpose-bred dogs. PROCEDURES In a randomized crossover study, each dog was anesthetized twice, and pneumoperitoneum was created with standard-temperature CO₂ (STCO₂; 22°C and 0% relative humidity) and WHCO₂ (37°C and 98% relative humidity). Data were collected during each procedure, including core body temperature, cardiorespiratory and thromboelastography variables, and inflammatory biomarkers. Peritoneal biopsy specimens were collected and evaluated with scanning electron microscopy. Dogs were assessed for signs of postoperative pain. RESULTS Mean core body temperature was significantly lower (35.2°C; 95% confidence interval, 34.5° to 35.8°C) with WHCO₂ than with STCO₂ (35.9°C; 95% confidence interval, 35.3° to 36.6°C) across all time points. Cardiac index increased during the procedure for both treatments but was not significantly different between treatments. Thromboelastography variables did not differ significantly between treatments as indicated by the coagulation index. Subjective evaluation of peritoneal biopsy specimens revealed mesothelial cell loss with STCO₂. There was no significant difference in circulating C-reactive protein or interleukin-6 concentrations. There was a significant increase in the number of postoperative pain scores > 0 for the WHCO₂ treatment versus the STCO₂ treatment. CONCLUSIONS AND CLINICAL RELEVANCE Analysis of these data suggested that effects on evaluated variables attributable to the use of WHCO₂ for creating pneumoperitoneum in healthy mature dogs undergoing laparoscopy did not differ from effects for the use of STCO₂.

Hyperthermic carbon dioxide pneumoperitoneum reinforces the inhibition of 5-FU on the proliferation and invasion of colon cancer

The effect of hyperthermic carbon dioxide (CO2) pneumoperitoneum in combination with 5-fluorouracil (5-FU) on the proliferation and invasion of colon cancer was explored. Colon cancer cell line SW-480 was sealed into the urine collection bag to simulate pneumoperitoneum with 100% CO2 under a pressure of 12 mmHg. The cells were divided into group A, CO2 at 37˚C; group B, CO2 at 43˚C; group C, 5-FU; group D, CO2 at 37˚C+5-FU; group E, CO2 at 43˚C+5-FU; and control groups under normal culture conditions. The cell proliferation was assessed by CCK-8 test; the cell apoptosis was tested by FACS analysis; the cell invasion was examined by Transwell assay; the expression of HSP-70, caspase-3, HIF-1α and MMP-9 proteins and genes were detected by western blot analysis and RT-PCR. The SW-480 cells were injected into nude mouse cecum subserosal to establish a colon cancer model. We applied 43˚C CO2 pneumoperitoneum or 5-FU intraperitoneal chemotherapy to intervene, detected the transplantation tumor growth and metastasis. The cell proliferation was inhibited in groups B, C, D and E, apoptosis was induced in groups B, C, D and E, the Transwell cell number decreased in groups B, C, D and E, the transplantation tumor weight and metastasis rate were inhibited in groups B, C, D and E, but all not in group A. The most significant change was observed in group E. Hyperthermic CO2 pneumoperitoneum was able to reinforce the inhibition of 5-FU on proliferation and invasion of colon cancer.